1. Field of the Invention
The invention pertains to a device for inductively supplying power and guiding a mobile object.
2. Prior Art
The inductive transmission of power enables power to be supplied to a mobile load without mechanical or electrical contact. Devices provided for this purpose, like those known, e.g., from WO 92/17929, include a primary part and a secondary part, which are electromagnetically coupled similarly in principle to a transformer. The primary part consists of supply electronics and a conductor loop laid along a path with forward and return conductors, which extend parallel to each other and transition into each other or are connected to each other at the end of the path. One or more pickups arranged on mobile loads and the associated pickup circuitry form the secondary part. In contrast to transformers of typical construction, this is a loosely coupled system, which is operated at a relatively high frequency in the kilohertz range and can bridge large air gaps up to a few centimeters. The advantages of this type of power delivery include, especially, freedom from wear and tear and maintenance, as well as contact safety and good availability. Typical applications include not only automatic material transport systems in manufacturing technology but also human transport systems, such as elevators and electric buses.
In such a device, because the path over which the load moves may not deviate from the course of the conductor loop, the load must be guided accordingly if it is not a rail-bound vehicle. Such guidance can be realized, e.g., such that the vehicle has a turning front axle, whose angular position is determined directly by a control surface, which slides in a groove running in the vehicle. Here, the pickup is advantageously arranged on this articulated front axle, so that it is always aligned as best as possible to the conductor loop embedded in the travel surface, even along curves. Disadvantages of this solution include the labor required to cut the groove, the unevenness of the travel surface, and the inevitable mechanical wear of the control surface.
One elegant solution, which avoids these disadvantages, is the noncontact inductive guidance described in DE 198 16 762 A1. In this way, the magnetic field transmitted by the conductor loop is detected by an inductive sensor arrangement, whose output signals are supplied to an evaluation device, which determines from these signals the position of the vehicle in the transverse direction to the conductor loop and controls servomotors as a function of this position for steering the vehicle. The provided sensor arrangement is arranged in the center in the vehicle and consists of one sensor with vertical and horizontal sensitivity axes, where the latter runs perpendicular to the direction of travel. Because the current in the forward and return conductors of the conductor loop is equal and opposite at every point in time, in the center position of the vehicle with reference to the conductor loop, the signal of the sensor with a vertical sensitivity axis reaches a maximum while the signal of the other sensor is null.
Frequently, in automatic transport systems there is the need for data communication between the vehicles and a central control station. For this purpose, from DE 39 16 610 A1, a device for simultaneous track guidance and data transmission is known, wherein, however, the track-guidance conductor is used exclusively for track guidance and not for supplying power to the vehicle. The sensor arrangement provided for track guidance completely agrees with the previous description, while the transmitter and receiver device for data communication is not explained in more detail.